The dependence of the time constant of left ventricular isovolumic relaxation (tau) on pericardial pressure.
The dependence of the time constant of left ventricular isovolumic relaxation (tau) on pericardial pressure.
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左心室等容舒张 (tau) 时间常数对心包压力的依赖性。
DOI：
10.1161/01.cir.81.3.1071
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发表时间：
1990
期刊：
影响因子：
37.8
通讯作者：
J. Tyberg
中科院分区：
文献类型：
--
作者：
M. Frais;D. Bergman;I. Kingma;O. Smiseth;E. Smith;J. Tyberg
本研究的目的是研究tau（左心室（LV）等容舒张的时间常数）对心包压的依赖性，并比较由先前研究者的方法和标准指数曲线拟合确定的tau值。所有最近的方法都涉及一个附加参数--指数松弛最终下降到的压力（PB，克雷格和穆尔戈方法中的压力截距，以及指数拟合中的渐近线）。本研究的另一个目的是确定这些参数与心包压力的关系。在8只闭胸麻醉犬中，通过每种方法根据腔内（Plv）和透壁LV压（Plv = Plv-Pper）计算tau，因为心包输注和静脉容量负荷改变了心包（Pper）和LV舒张末期压。通过韦斯等人的方法确定的时间常数取决于心包压力;通过其他方法确定的时间常数则不依赖于心包压力。PB和渐近线被发现是相似的，增加几乎等同于心包压力。当心包压力为零时，这些值约为-20 mm Hg。因此，这两个参数似乎指示相同的基线压力，该压力与心包压力同步增加。报告的通过韦斯等人的方法根据腔内LV压力计算的tau值的变化可能反映LV舒张功能变化以外的因素。
The purpose of this study was to investigate the dependence of tau, the time constant of left ventricular (LV) isovolumic relaxation, on pericardial pressure and to compare values of tau as determined by the methods of previous investigators and by a standard exponential curve fit. All of the more recent methods involve an additional parameter--the pressure to which the exponential relaxation finally declines (PB, the pressure intercept in the method of Craig and Murgo and the asymptote in the exponential fits). An additional purpose of the study was to determine the relation of these parameters to pericardial pressure. In eight closed-chest anesthetized dogs, tau was calculated from intracavitary (Plv) and transmural LV pressure (Plv = Plv-Pper) by each method as pericardial (Pper) and LV end-diastolic pressure were changed by pericardial infusion and intravenous volume loading. The time constant determined by the method of Weiss et al was dependent on pericardial pressure; the time constants determined by the other methods were not. PB and the asymptotes were found to be similar and to increase almost equally with pericardial pressure. When pericardial pressure was zero, these values were approximately -20 mm Hg. Thus, both these parameters seem to indicate the same baseline pressure, a pressure that increases pari passu with pericardial pressure. Reported changes in the value of tau calculated from intracavitary LV pressure by the method of Weiss et al may reflect factors other than changes in LV diastolic function.
不完全左心室舒张的量化：与等容压下降时间常数的关系。
影响因子：
39.3
作者：
Weisfeldt,ML;Weiss,JL;Frederiksen,JT;Yin,FC
通讯作者：
Yin,FC